Tarbela Dam, found on the Indus River in Northern Pakistan, is the largest earth-filled dam in the world. The dam was completed in 1976 as the result of a water-rights agreement between India and Pakistan. It is 143m high and almost 3km wide, for a total volume of 106million cubic metres of rocks and earth, making it one of the world’s largest man-made structures. It holds back a reservoir almost 100km long, though the capacity of the lake has been reduced by silt deposits, just one of many problems encountered by the dam’s builders and operators. The water…